1. Field of the Invention
The field of art to which this invention pertains is transistor biasing circuits and in particular to circuits for stabilizing the DC collector currents of a pair of transistors regardless of variations in the factor h.sub.FE.
2. Description of the Prior Art
Prior art transistor biasing circuits have been designed to produce predetermined collector currents for two transistors under given design criteria, however, under other criteria such as using one of the transistors as an attenuator, all of the requirements of such a circuit are not met by the prior art. For instance, certain resistance values in the circuit cannot be changed at will without affecting the input impedance of one of the stages or the dynamic range of operation of the circuit. Other resistance values must be maintained in order to prevent undesirable thermal noise.
A detailed description of two prior art circuits shown in FIGS. 1 and 2 is made in the section below entitled "Description of the Preferred Embodiment" in view of the fact that this detailed circuit description is closely related to portions of the circuit description of the invention shown in FIGS. 3 thru 7.
Reference is had to related application Ser. No. 635,365 assigned to same assignee and filed on even date herewith.